What Is RSI in Crypto? (With Examples From Bitcoin & Ethereum)

What Is RSI?

The Relative Strength Index (RSI) is a momentum oscillator developed by J. Welles Wilder in 1978. It measures the speed and magnitude of recent price changes on a scale from 0 to 100, helping traders identify whether an asset is overbought or oversold.

RSI compares the average gain of up-days to the average loss of down-days over a lookback period — typically 14 days for daily charts. The result is a single number between 0 and 100.

How to Read RSI

There are three zones to know:

• RSI below 30 — Oversold: Selling pressure has been excessive. The asset may be undervalued and ripe for a bounce. This is considered a potential buy signal.
• RSI above 70 — Overbought: Buying pressure has been excessive. The asset may be overextended and due for a pullback. This is considered a potential sell or take-profit signal.
• RSI between 30 and 70 — Neutral: No extreme momentum in either direction. Most day-to-day readings fall here.

RSI Example: Bitcoin

Bitcoin (BTC) regularly tests the RSI oversold zone during major corrections. During the 2022 bear market, BTC's RSI dropped below 20 on the daily chart multiple times — each time coinciding with a significant low or temporary bounce.

Conversely, during the 2021 bull run, BTC's RSI spent weeks above 70 and even reached 85+. Traders who sold every time RSI crossed 70 missed large portions of the rally. This is why RSI is best used alongside trend indicators like EMA cross.

RSI Example: Ethereum

Ethereum (ETH) tends to show sharper RSI swings than Bitcoin due to its higher volatility. During ETH's major rallies, RSI frequently reaches 75–80 before correcting. During sell-offs, RSI can drop below 25.

A practical rule many traders use: look for RSI to enter oversold territory (below 30), then wait for it to cross back above 30 before entering a position. This crossing-back confirms the worst of the selling pressure is over.

RSI Divergence

One of the most powerful RSI signals is divergence — when price makes a new high but RSI makes a lower high (bearish divergence), or price makes a new low but RSI makes a higher low (bullish divergence).

• Bullish divergence: Price lower low + RSI higher low → possible reversal upward
• Bearish divergence: Price higher high + RSI lower high → possible reversal downward

RSI Limitations

RSI can stay overbought or oversold for extended periods in strong trends. A coin in a powerful bull trend can have RSI above 70 for weeks while continuing to rise. Always combine RSI with at least one trend indicator (like EMA cross or MACD) before acting on its signal alone.

Summary